Comprehensive Guide to Spring Boot, Spring MVC, and JPA Annotations

Annotations List

A quick enumeration of frequently used Spring annotations such as @SpringBootApplication, @Configuration, @EnableAutoConfiguration, @ComponentScan, @Component, @RestController, @Autowired, @PathVariable, @JsonBackReference, and @RepositoryRestResource.

Annotations Detailed Explanation

@SpringBootApplication : Combines @Configuration, @EnableAutoConfiguration, and @ComponentScan to enable automatic configuration and component scanning.

package com.example.myproject;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication // same as @Configuration @EnableAutoConfiguration @ComponentScan
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

@ResponseBody : Directly writes the method return value to the HTTP response body, typically used for RESTful APIs.

@RequestMapping("/test")
@ResponseBody
public String test(){
    return "ok";
}

@Controller : Marks a class as a Spring MVC controller; methods are usually mapped with @RequestMapping.

@Controller
@RequestMapping("/demoInfo")
public class DemoController {
    @Autowired
    private DemoInfoService demoInfoService;

    @RequestMapping("/hello")
    public String hello(Map<String,Object> map){
        System.out.println("DemoController.hello()");
        map.put("hello","from DemoController.helloHtml");
        // renders hello.html or hello.ftl
        return "/hello";
    }
}

@RestController : Shortcut for @Controller + @ResponseBody, used for REST‑style controllers.

@RestController
@RequestMapping("/demoInfo2")
public class DemoController2 {
    @RequestMapping("/test")
    public String test(){
        return "ok";
    }
}

@RequestMapping : Defines URL routing for controllers and methods, supporting attributes like params, headers, value, method, consumes, and produces.

@RequestParam and @PathVariable : Bind request parameters and path variables to method arguments.

@RequestMapping("user/get/mac/{macAddress}")
public String getByMacAddress(@PathVariable String macAddress){
    // do something
}

JPA Annotations

Key persistence annotations include @Entity, @Table, @MappedSuperclass, @Id, @GeneratedValue, @SequenceGenerator, @Column, @Transient, @JsonIgnore, @JoinColumn, and relationship mappings like @OneToOne, @OneToMany, @ManyToOne.

Spring MVC Related Annotations

Beyond @RequestMapping, Spring MVC uses @RequestParam for query/form parameters and @PathVariable for URL segments, enabling fine‑grained request handling.

Global Exception Handling

@ControllerAdvice marks a class for cross‑cutting concerns such as centralized exception handling, while @ExceptionHandler defines methods to process specific exception types.